1. Field of the Invention
The present invention relates to a molding process, and more particularly to a method of continuously feeding film pieces for a molding process.
2. Description of the Related Art
Thin film processes and tasks are incorporated in many industries. FIGS. 1 to 5 show a film feeding machine 1 and a die assembly 2 having a first die member 2a and a second die member 2b which are incorporated in a film molding process. The film feeding machine 1 includes a reel 3 and a clip device 4 above and under the die assembly 2. A roll of a film 5 is mounted on the reel 3 to provide the film 5 between the first die member 2a and the second die member 2b, and the clip device 4 holds the film at an opposite side of the die assembly 2. A heater 6 is moved to a position between the first die member 29a and the second die member 2b and moved toward the film 5 to press the film 5 on the second die member 2b and heat it. Next, the film 5 is suck on a sidewall of a recess of the second die member 2b by vacuum, and then the first die member 2a and the second die member 2b are combined together for injection molding process. After the injection molding process, the film 5 is cut off and the clip device 4 releases the residual film 5a (referring to FIG. 5) to get a product 7 with the film on a surface thereof after the die assembly 2 is opened. Above steps may be repeated for mass production.
However, above process must have the clip device 4 to straight the film 5 from the roll and the film 5 must extend out of the die assembly 2 to be held by the clip device 4, therefore there always is a section of the film 5 being cut off every time when the product is molded. The cut-off film is waste (referring to FIG. 4 and FIG. 5) and there will be a greater amount of the film being waste in mass production. In addition, the reel 3 and the clip device 4 can not provide the film 5 with a precise tension that may cause the injection molding process failure. Again, the above process must include the step of cutting the film off that increases the time of the whole process. The heater 6 is an external device, which must have a controller to be operated, and it increases the space and cost for the whole equipment.